mRNA and cell surface expression of proteases and endogenous protease inhibitors in CD4⁺T cells and SupT1 cells. (A) Total RNA from CD4⁺ T cells stimulated with ConA for 3 days and SupT1 lymphoma cells was subjected to RT-PCR (30 cycles). Fragment lengths conformed to the expected size. No mRNA was detected for MMP-8, -13, cathepsin B and K in either cell type (not shown). Positive controls were performed from HT-1080/MT1 or HT-1080/neo cells (MMP-7 and -9). RT indicates reverse transcriptase reaction. (B) Flow cytometry of MT1-MMP surface expression (gray histogram) in ConA-T blasts and positive control cells (HT-1080/MT1) as compared with isotype control (white histogram).